El Greco's 'Mary Magdalene in Penitence'

El Greco's Mary Magdalene in Penitence has a nipple showing. It was painted around 1577 shortly after his arrival in Toledo, Spain, as part of a series (the other paintings are more discreet). Some critics believe it is a portrait of his mistress, Jerónima de las Cuevas, with whom he had a son the following year. They lived together for the rest of his life although they never married (possibly because he had a wife back in Italy).

Compare this with the later painting, below, of the Virgin Mary, one of several versions he did at the time. This a much better painting - 20 years later - El Greco had turned darker at this point in his career.